Effect of essential amino acid supplementation and aerobic exercise on insulin sensitivity in healthy older adults: A randomized clinical trial

Amanda C. Randolph, Melissa M. Markofski, Blake B. Rasmussen, Elena Volpi

Research output: Contribution to journalArticle

Abstract

Background & aims: The combination of prolonged essential amino acid (EAA) supplementation and aerobic exercise training (Ex) improves muscle protein metabolism, strength and function in healthy older adults. However, excess EAA intake may worsen insulin sensitivity. Here we report the effects of EAA supplementation (EAA, n = 11), placebo (PLA, n = 10), aerobic exercise with placebo (Ex + PLA, n = 11) or Ex with EAA supplementation (Ex + EAA, n = 10) for 22 weeks on insulin sensitivity in non-diabetic older adults. Methods: A 2 × 2 design with block randomization and double blinding for supplement or placebo was used. Subjects ingested EAA (15 g) or placebo daily. Exercising subjects participated in supervised progressive vigorous treadmill walking 3 times weekly. Measures of insulin sensitivity by oral glucose tolerance testing were collected at baseline and 22 weeks. Dietary intakes of protein and specific amino acids were determined in a subset of subjects. Results: Overall, exercise improved insulin sensitivity, while EAA supplementation had no effect. In the dietary subset, post-intervention insulin sensitivity did not correlate significantly with the total intake of EAA, anti-angiogenic amino acids (cysteine, methionine), or branched-chain amino acids (isoleucine, leucine, valine). Conclusions: Overall, we conclude that in healthy older adults with moderate protein intake, EAA supplementation is metabolically safe as it does not decrease insulin sensitivity regardless of its combination with aerobic exercise. Thus, daily protein intake should be controlled for when modeling insulin sensitivity. Future studies should explore the role of increased blood flow as a potential explanatory factor for the observed interaction between aerobic exercise and supplementation. Clinical trial registration number: NCT00872911.

Original languageEnglish (US)
Pages (from-to)1371-1378
Number of pages8
JournalClinical Nutrition
Volume39
Issue number5
DOIs
StatePublished - May 2020

Keywords

  • Glucose metabolism
  • Matsuda index
  • Sarcopenia

ASJC Scopus subject areas

  • Nutrition and Dietetics
  • Critical Care and Intensive Care Medicine

Fingerprint Dive into the research topics of 'Effect of essential amino acid supplementation and aerobic exercise on insulin sensitivity in healthy older adults: A randomized clinical trial'. Together they form a unique fingerprint.

  • Cite this